My own personal Lovecraft system.

I'm mostly just posting this for a pbp game but you can read it casually too.

Scholar (you know a lot about just one thing, but it can help sometimes!)

Nice clothes, equipment for your field, academic book, strange trinket.

-You are skilled in an academic field (mathematics, chemistry, etc) and

know an absurd amount about it. Assume all related knowledge is known automatically.

-You gain +1 die in regards to your academic field. 

-You cannot lose sanity from talking or reading about sanity-damaging subjects,

only by witnessing them. This allows you to teach someone else without hurting them as well. 

Investigator (the default cosmic horror adventurer)

Street clothes, journal, pen, hand weapon, vice of choice (alcohol, cigarettes, etc). 

-Heal 1d4 Sanity when you indulge in the vice you choose when you make your character

(smoking, drinking, gambling, etc).

-You gain +1 die where perception is involved.

-You can gather clues others would miss, allowing you to ask 1 extra question about the nature of

any scene you encounter. 

Monster Hunter (you’re not gonna shoot cthulhu, but you might fuck up some deep ones)

Protective clothes, big weapon, two hand weapons, bandages. 

-If something has caused you to lose sanity, killing, capturing, or dominating it will restore half

the lost sanity. This only applies if you were the most important factor in it’s destruction.

-You gain +1 die when fighting.

-Unless the thing you’re fighting is omnipotent, or more than triple your size, you can try and fight it.

Treat most things you can fight as basically other armed humans. 

Coward (the normal human response to getting spat at by mi-gos)

Disheveled clothes, light source, hand weapon, running shoes. 

-When you drop to 0 Sanity, you are able to still act as long as all you do is run.

Once you get away from what caused you to drop to 0, you regain 1 sanity.

-You get +1 die when avoiding conflict.

-You always know the direction of the most dangerous thing within reasonable distance.

The sense becomes stronger as it gets closer.

Alien (Use a little bit of magic to fight the magic, but use too much and you’ll go mad)

Strange clothes, occult items, alien marks, ancient currency.

-You have a single eldritch trait, such as superhuman durability or the ability to summon tiny imps.

Using this is deeply unpleasant, and causes you to lose 1d4 sanity. 

-You gain +1 die when dealing with magic. 

-You are immune to sanity “chip damage” so to speak. If you take only 1 sanity damage,

you take none instead

Bankroll (just some rich idiot along for the ride)

Extravagant clothes, various jewelry, wads of cash, business cards.

-As long as you babble incoherently about how Things Like These don’t happen to People Like You

(and don’t help) you don’t lose sanity. You can’t go back to babbling once you stop. 

-You gain +1 to social rolls when you have money in someone’s face.

-You are incredibly, incredibly wealthy. Treat anything up to about 1000 dollars as pocket change,

and anything up to a Rolls Royce as a business expense.

Druggie (you sell to dealers, you buy from dealers. It’s dealers all the way down)

Stained clothes, chemical equipment, a wad of psychoactive drugs, a wad of medicinal drugs.

-If you are high, you lose 1 less sanity from all sources. If you get drugs into someone else, they 

get the same benefit, although there are consequences for giving drugs out for free.

-You gain +1 die to know about or apply drugs.

-When you make a druggie, choose one of the following professionals your drug knowledge

basically makes you: Medic, Therapist, or Toxicologist. 

Criminal (you skullduggerous fiend, you)

Dark clothes, Illegal goods, fake ID, hand weapon.

-If you are dropped to 0 sanity, you are allowed to hide instead of sitting and cowering.

Once you are safe, you return to ordinary cowering. 

-Gain +1 die to rolls involving stealth and skullduggery..

-You have enough money/blackmail/favors to get one person to do something dangerous/difficult f

or you each mission. They will be an untrustworthy criminal.

Begin play with 10 health and 10 sanity. At 0 health, you are knocked unconscious.

If you lose health while still unconscious, you perish. At 0 sanity, you spend 10 minutes helpless

and terrified and then regain 1 sanity. You also become Unstable. Once you reach 10 sanity again

you remove Instability. If you are dropped to 0 sanity while Unstable, go mad and lose your

character to the evil darkness or whatever.

Anyone can attack HP, doing 1d6 damage with a hand weapon, 1d6+2 with a big weapon,

and adding an extra die if attacking a weak point (burning a shoggoth, sending dogs after a

Whately). Monsters can attack Sanity, doing 1d6 if they’re an abomination or 1d6+2 if they're a god,

and adding an extra die if attacking a weak point (trapping a claustrophobe, blinding a nyctophobe)

Choose for your character a phobia that makes them more vulnerable to particular scary things,

and a vice they can indulge in to restore 1 sanity (or 1d4 for an investigator!). Then put a 3, 2, and

1 in the stats of Body, Mind, and Charm. Roll d6s equal to stat to defy danger, succeeding

if you get at least one 6. You can get bonuses based on skills afforded by your class.